Electrodeless metal halide lamps, in general, have an electrodeless discharge vessel containing an ionizable discharge medium. An electric field produces a light-emitting plasma discharge from the ionizable discharge medium within the discharge vessel. The applied electric field is produced by an exciter. The exciter delivers radio frequency (RF), or more particularly ultra-high frequency (UHF), electric field to the discharge vessel and may be a separate unit which may need to be incorporated within the lamp.
Typically, the discharge medium may be in a gas or a vapor phase and is contained by the discharge vessel. As the ionized atoms and molecules relax to a lower energy state, they emit radiation. The discharge vessel is capable of transmitting the generated radiation out of the discharge vessel. Most of the currently used discharge radiation sources contain mercury as a component of the ionizable discharge medium due to its efficient discharge characteristics.
Accidental release or routine end-of-life disposal of mercury-containing ionizable discharge source medium may be potentially harmful to the environment and/or present immediate health concerns. Therefore, there is a need to develop a mercury-free discharge composition and a lamp with improved efficiency.